A square-wave converter in an ac distributed power system is typically simple to implement and has a lower voltage rating than an equivalent sine-wave converter. Moreover, a square-wave converter has lower line current harmonics if the majority of loads are non-linear (e.g., rectifiers). However, if fast transitions are allowed during switching of the square wave, currents flow in parasitic capacitances to ground, and the higher frequency components thereof can cause both conducted and radiated interference with sensitive equipment.
Accordingly, it is desirable to provide a square-wave converter which limits the rate of change of voltage (i.e., the slew rate) on an ac distribution bus in order to reduce interference due to parasitic system capacitances. Furthermore, it is also desirable to present a low driving point impedance to the ac distribution bus so that the bus voltage does not vary substantially with the load. Still further, it is desirable to provide such a square-wave converter which operates with zero-voltage switching of the power switches and is thus highly efficient.